1. Field of the Invention
The present invention relates to a proportional control actuator and, more particularly, to a rotary actuator of the type which uses a proportional solenoid, in which an angle of rotation of a rotating shaft is determined by the balance between a rotational torque of a rotary magnet and the restoring force of a restoring spring.
2. Description of the Prior Art
In a conventional proportional control actuator for driving a fluid control valve, a proportional solenoid and a core move linearly relative to each other. For this reason, the stroke of the core or solenoid is small, and a fluid channel must therefore be enlarged in cross-sectional area in order to perform flow rate control of a large amount of fluid. This results in a very large fluid control valve. Furthermore, since the core or solenoid moves linearly, the overall actuator is subject to mechanical vibration.